Espresso drinks, in comparison to other coffee drinks, are noted for a fine layer of bubbles (“crema”) that settles on the top of the drink from fine bubbles that are interspersed within the drink during the brewing process. Coffee consumers in many markets view a crema as a key indicator of a good cup of espresso. Espresso and other coffee and milk drinks are sometimes prepared by mixing a powder or fluid concentrate in water. However, the quality perception of theses drinks is sometimes an issue if the crema does not resemble that when the espresso is prepared from ground coffee.
Mixing devices are known for speedier preparation of coffee, espresso, and other such beverages and other foods by mixing a powdered or liquid concentrate food component with a liquid, such as water. These devices typically feed the powdered or concentrate component into the water, which is often pumped tangentially into a mixing chamber to create a whirlpool to mix the powder or concentrate into the water. When these products are reconstituted in a dispenser, the process does not follow the same steps as a roast and ground espresso product so a fine layer crema is not generated. Instead, a layer of undesirable large bubbles (“foam”) may be generated, the magnitude dependent on the particular recipe of the powder or concentrate and the flow path for dispensing. To the consumer these bubbles could indicate that the coffee was not made correctly.
In known mixing devices, the mixture is then fed to a whipping mechanism, which is usually a rotating plate. The plate aerates the mixture and produces a froth. The frothed mixture is usually dispensed into a container for drinking. Such known whipping mechanisms, however, may only increase the amount of foam present in the coffee because the froth that they produce is aimed at producing bubbles that are much larger than those that distinguish crema.
U.S. Pat. No. 5,927,553, for example, discloses a mixing and dispensing apparatus with a cruciform frothing blade. Other shapes of frothing blades are also known. For instance, companies such as Rhea and Zanussi use whippers with an axially short disk with very steep sloped walls. U.S. Pat. No. 7,059,498, for example, discusses a mixing device including a conical whipping rotor that is configured to produce large bubbles within a beverage so as to form a layer of foam along the top of the beverage. Other whippers have disks with independent ramps extending from a substantially flat plate. The known devices generally have their greatest efficiency for preparing a small group of products.
Therefore, there is a need for a mixing device with an improved whipping mechanism that reduces or eliminates the production of large bubbles or foam in favor of finer bubbles.
Furthermore, crema generation is often benefited by slow flow speeds, whereas when filling a carafe with a large amount of “American style” coffee, speed is favored and crema production may not even be desirable. If dispensed into a multi-cup carafe for a server to pour from, the large bubbles can often prevent full filling of the carafe if they are overflowing from the top. For this solution, a system is needed that does not produce bubbles or crema and is able to rapidly fill a carafe.